RT-qPCR validation of the microarray data. Expression of 14 genes was determined using RT-qPCR for the wild type and rsh mutant in early exponential phase and stationary phase. The log2-transformed mean values of two biological replicates were used to report three different fold changes for each gene (Y-axis) compared to the respective microarray fold changes (X-axis). See Additional file 6 for a complete list of the plotted fold change values. Red dots, wild type stationary phase versus early exponential phase. Blue diamonds, wild type versus rsh mutant in stationary phase. Green squares, wild type versus rsh mutant in exponential phase. The fold changes for ecfG2/PF00052, CH00371 and prkA/CH02817 are indicated.